The present invention, in some embodiments thereof, relates to cancer diagnosis and, more particularly, but not exclusively, to methods and systems of evaluating a risk of cancer.
A diagnosis of colorectal cancer includes diagnosis based on the immunological fecal occult blood reaction, diagnosis by colonoscopy, and the like. However, diagnosis based on a fecal occult blood test does not serve as definitive diagnosis, and most of the persons with positive-finding are false-positive. Furthermore, in regard to early colorectal cancer, there is a concern that both the detection sensitivity and the detection specificity become lower in the diagnosis based on a fecal occult blood test or the diagnosis by colonoscopy. In particular, early cancer in the right side colon is frequently overlooked when diagnosed by a fecal occult blood test. Diagnostic imaging by CT (computer tomography), MRI (magnetic resonance imaging), PET (positron emission computerized-tomography) or the like is not suitable for the diagnosis of colorectal cancer.
On the other hand, colorectal biopsy by colonoscopy serves as definitive diagnosis, but is a highly invasive examination, and implementing colonoscopic examination at the screening stage is not practical. Furthermore, invasive diagnosis such as colonoscopy gives a burden to individuals such as accompanying pain, and there may also be a risk of bleeding upon examination, or the like.
During the last years, some new methods have been developed for diagnosis of colorectal cancer. For example, U.S. Patent Application Publication No. 2010/0009401 describes a method of evaluating colorectal cancer, where amino acid concentration data on the concentration value of amino acid in blood collected from a subject to be evaluated is measured, and a colorectal cancer state in the subject is evaluated based on the concentration value of at least one of Arg, Cys, Om, Trp, Glu, ABA, Val, Phe, Leu, GIn, Ile and His contained in the measured amino acid concentration data of the subject.